在尝试向python字典添加新密钥时获取keyerror python

Question

在下一段代码中，当我试图向字典添加新键时，会收到一个KeyError。

def tournamentWinner(competitions, results):
record = {}
winner = None
for i in range(len(results)):
if results[i] == 0:
if record[competitions[i][1]] not in record:
record[competitions[i][1]] = 3
else:
record[competitions[i][1]] += 3
else:
if record[competitions[i][0]] not in record:
record[competitions[i][0]] = 3
else:
record[competitions[i][0]] += 3
for element in record:
if winner is None:
winner = element
if element > winner:
winner = elemnt
return winner

我得到这个密钥错误：

Exception Detected: 
Traceback (most recent call last):
File "/tester/program.py", line 7, in tournamentWinner
if record[competitions[i][1]] not in record:
KeyError: 'C#'

Answer 1

您收到该错误是因为在使用if-else检查competitions[i][1]密钥时，record中不存在该密钥。

你可以使用dict.get方法来解决这个问题：

如果其他：

if record[competitions[i][1]] not in record:
record[competitions[i][1]] = 3
else:
record[competitions[i][1]] += 3

你可以使用

record[competitions[i][1]] = record.get(competitions[i][1], 0) + 3